Heating stove



Feb. 5, 1946. w. A. GRISWOLD 2,394,441

HEATING STOVE Original Filed May 30, 1942 3 Sheets-Sheet l lNV ENTOR WILLIAM A.

ATTORN EYS HEATING STOVE Original Filed May 30, 1942 3 Sheets-Sheet 2 INVENTOR WILLIAM A. emswow TQM; mum

ATTORNEYS Feb. 5, 1946.

W. A. GRISWOLD HEATING STOVE Original Filed May 30, 1942 3 Sheets-Sheet 3 INVENTOR WILLIAM A. GRISWOLD ATTORNEYS Patented Feb. s, 1946 NITED STATE HEATING STOVE William A. Griswold. Cleveland, Tenn.

Original 445,169. 1943, Serial No.

application May 30, 1942, Serial No.

Divided am this application May 24.

1 Claim. (01. ice-s1) This invention relates to heating appliances and particularly heating stoves adapted to be used within a room of a dwelling or other area to be heated.

An object of the invention is to provide an automatic draft control that utilizes the normal expansion of the walls of the combustion chamber for regulating the quantity of air supplied to the fuel in the combustion chamber.

Another object of the invention is to provide a heating appliance that will heat both through radiation and recirculation of air.

Another object of the invention is to provide an automatic control for the air supplied beneath the fuel bed in a heating appliance that automatically reduces the quantity of air supplied to the fuel bed in response to an increase in temperature of the combustion chamber.

Another object of the invention is to provide an automatic control over the quantity of air supplied to the fuel bed of a heating appliance wherein .a portion of the control mechanism is maintained at a lower temperature than another portion thereof, and the temperature diflerential of the portions of the mechanism is utilized to actuate an air supply control member.

Another object of the invention is to provide an automatic draft control for the fuel bed of a heating appliance in accordance with the foregoing obiect wherein a part of the control mechanism consists of the wall of the combustion chamber of the heating appliance.

Another object of the invention is to provide a heating appliance wherein a primary source of air is supplied beneath the fuel bed, and a secondary source of air is preheated and applied above the fuel bed to complete combustion of the products of combustion of the fuel, wherein the primary source of air is under automatic control to regulate the draft through the fuel bed.

Another object of the invention is to provide a heating appliance wherein a primary air supply is provided beneath the fuel bed of the heating appliance for producing a draft therethrough, and a second air supply is directed within the combustion chamber of the heating appliance but is prevented from engaging the fuel bed until the secondary air reaches a point above the fuel bed for completing combustion of the products of combustion from the fuel bed.

Another object of the invention is to provide a heating appliance wherein the combustion chamber is partially enclosed so that a portion of the chamber can heat an area by radiation -the foregoing objects while the enclosed portion will heat an area by circulation of air within the area.

It is still another object of the invention to provide a heating appliance in accordance with wherein a draft control member for the fuel bed is disposed within one of the air circulating portions of the heating appliance so that the draft control member will be maintained at a lower temperature than the combustion chamber of the heating appliance, whereby the temperature differential between the draft control member and the combustion chamber is utilized as the actuating power for controlling operation of an air supply member that supplies air to the fuel bed of the heating appliance.

Further objects and advantages will become apparent from the drawings and the following description.

This application is a division of my application No. 445,169, filed May 30, 1942, and now abandoned.

In the drawings:

Figure 1 is a perspective elevational view of a heating appliance constructed and arranged in accordance with the teachings of this inventionr Figure 2 is a transverse cross-sectional view of the heating appliance taken along line 2-2 of Figure 3.

the heating appliance Figure 2.

Figure 4 is an elevational view of the draft control apparatus of this invention.

Figure 5 is a side elevational view, partially in cross-section of the draft control apparatus.

The heating appliance or stove of this invention is adapted to be used within a room of a dwelling or other area to be heated for increasing the temperature of the air within the room by radiation and recirculation of the air.

When the heating appliance or stove is loaded with fuel the intensity of the fire gradually increases as long as the draft through the fuel bed remains the same. The usual heating stove requires considerable personal attention to prevent the same from overheating, the drafts for the fuel bed requiring constant manipulation to regulate the same and establish a proper to the fuel within the combustion chamber.

There is no assurance that after the drafts' have been set that the fuel bed will burn at an even rate because the intensity of the draft may change due to changing wind conditions outside the area being heated which eflects the flue draft taken along line 3-3 of Figure 3 is a vertical cross-sectional view of air supply sists of a base of the fire brick wall I9 for the heating appliance. Therefore, even though the drafts have been set some time after the fuel bed has started to burn vigorously there is no assurance that the air supply will not change to the fuel bed due to a different draft condition.

The combination chamber of the stove or heating appliance varies considerably in temperature ranging anywhere from substantially room temperature with a low fire to red heat when the fire is burning vigorously. As a result the wall from which the combustion chamber is constructed expands and contracts in direct proportion to the temperature variation-of the wall. This invention utilizes the normal contraction and expansion of the wall of the combustion chamber as a part of an actuating system to automatically control the draft to the fuel bed of a heating appliance in response to the temperatureof the wall of the combustion chamber, so that as the temperature of the chamber rises the draft to the fuel bed will be automatically reduced. The draft control of this invention can be manually set and the quantity of air supplied to the fuel bed will be automatically regulated to prevent overheating of the stove, as well as prevent underheating due to lack of air supply to the fuel bed.

In particular, the invention relates to a heating appliance or stove of the type having the combustion chamber in the form of a magazine that is adapted to be filled with fuel about once a day. After the fuel bed has started burning the draft beneath the fuel bed can be manually set and thereafter the automatic draft control will increase or decrease the quantity of air supplied the fuel bed to maintain a substantially even combustion of the. fuel bed in response to the temperature'of the combustion chamber.

The heating appliance disclosed herein con- ID that supports a circular sheet metal wall forming the wall of the combustion chamber for the heating appliance. A wall l2 divides the cylindrical chamber formed by the wall into a combustion chamber l3 and an ash chamber I8. A bottom wall I5 is provided within the cylindrical wall upon which an ash pan |6 is supported. .The wall |2 is suitably supported upon the wall l5 by meanspf the bars ll. A grate I8 is provided adjacent the wall |2 for supporting the fuel within the combustion chamber l3.

The combustion chamber I 3 is lined with a fire brick wall l9 that is supported upon the horizontal wall I2 and forms the magazine to receive the fuel. The cylindrical wall supports a ring 20 upon th upper edge thereof, the ring 20 having an inverted cone shaped flange 2| extending downwardly therefrom. The lower edge 22 of the flange 2| is spaced from the upper edge 23 to provide an air space 24 through which air can be supplied over the top of the combustion chamber 3 in a manner to be hereinafter described.

A top closure wall 25 is provided for the heating appliance to which an access door 26 is hinged by means of the hing member 21. The combustion chamber it can be loaded through the door 26 to fill the magazine with fuel.

A baflle plate is secured to the closure wall 25 and has the sides thereof open to permit discharge of flue gases through the flue 29. The baflle plate 28 is of sufficient width to prevent a direct flow of the flue gases to the fine 29. the gases being directed around th edges of the .baille 28 to cause the same to enter the chamber 3| to the bottom provided between The primary source of air for the fuel within the combustion chamber I3 is admitted to the ash compartment I through the draft opening 32 that is closed by means of a draft'door 33. The draft door assembly consists of a frame 34 that is secured to the wall :01 the ash compartment l4 by meansof the bolts 35 and vhas the air' supply opening 32 therein. The draft door 33 is provided with a pair of lugs 38 through which a hinge wir 31 extends, the hinge wire also extending through the'lugs 38 carried upon the frame 34. The ash compartment I4 is provided with a suitable access door 39 in the front wall thereof. A secondary air within the combustion chamber |3 that is admitted, to the combustion air supply opening 40 provided in the rear wall of the combustion chamber. A baflle plate 4| is secured adjacent air into the combustion chamber as it flows upwardly along the side of the wall I A second source of secondary air is supplied through an opening 42 providedln the front wall of the combustion chamber l3. This opening is regulated by means of a draft door. 43 that is manually operated for controlling the quantity of secondary air supplied therethrough. The air' supplied through the openings 40 and 42 does not enter directly into the combustion chamber l3 but enters passages M and 45 disposed adjacent the openings so and d2 respectively. These passages 44 wall l9 by recessing a portion of the fire brick wall so that there'is a space between th wall at the top of the wall I9 consumes any unburnt combustible gases before they pass through the chamber 3| and the flue 29.

A draft control'member is provided for regulating the degree of opening of the draft door 33 and thereby controlling the quantity of primary air that is supplied through the grate l8 of the fuel'bed within the com- 3. This draft control member consists of a rod 46 having one end thereof slidably guided within a lug 41 extending from the draft door frame M. The lower end of the rod 46 engages a knife edge 48 provided on an arm 49 extending from the control handle 50 is'provided is supported upon a bracket 5| by means of a boss 55. The bracket 5| is secured to the wall H by means of the bolts or screws 52 that ex:- tend through slots 53 provided within the bracket 5| so thatthe bracket can be adjusted vertically upon the wall The lower face of the bracket 5| is provided .with a cam surface 54 that is engaged by a bar 55 carried by the boss 56 on the handle 50. The upper end of the rod 46 extends within a recess provided within the boss 56 for guiding the upper end of the rod 46 and supporting the same with 50.

When the handle bustion chamber 50 is rotatedupon the boss the bafll'e 28 and the fiue2l.

supply is provided chamber through anv the air opening 40 to direct and 45 are provided in the fire brick air is preheated in its passage for the rod and respect to the handle 56 the bar 55 will ride vertically upon the cam surface 54 thus moving the rod 46 vertically so that the lowerend thereof, that is in engagement with the knife edge 48, will cause the draft door 33 to b pivoted upon the hinge wire 31 and move with respect to the frame 34 and thus regulate the degree of opening of the air supply opening 32. Thus the degree of opening of the draft door 33 can be manually set to regulate the supply of primary air beneath the grate l8 and the fuel in the combustion chamber I3.

As the temperature of the wall II increases it will expand vertically as much as 1*; of an inch to g of an inch so that the actual dimension between the bracket 5| and the knife edge 48 increases when the temperature of the wall II increases. Since the rod 46 is spaced a substantial distance from the wall II of the combustion chamber, the rod 46 will be at a lower temperature than the wall H and thus will not expand to the same extent. In fact the temperature differential between the wall II and the rod 46 is quite high because the rod 46 is subjected to the air circulating within the room.

In view of the fact that the rod 46 does not expand to the same extent as the wall II of the combustion chamber the effective length of the rod actually becomes less so that the door 33 can swing downwardly to maintain the knife edge 48 against the bottom end of the rod 46.

It will thus be seen that the temperature diftion chamber cools down. That is the contraction of the wall I I decreases the actual dimension between the bracket 6| and the knife edge 48 so that the bottom end of the rod 46 is forced.

downwardly against the knife edge 48 to move the door 33 upwardly and thus increase the air inlet passage through the opening 32. The draft control mechanism thus provides an automatic control for regulating the supply of air beneath the fire bed In the combustion chamber I3 in direct response to the temperature of the combustion chamber. Regardless of the temperature of the combustion chamber at the time the draft control is manually set by the handle 60, the control will function in a manner heretofore described. In fact if the handle 50 is set to regulate the draft within a range of temperature lower than the temperature of the combustion chamber asreflected by the wall I I at the time the draft control is set, the draft door 33 will close to reduce the .quantity of air supplied beneath the fuel bed until the temperature of the wall II has reduced sufiiciently to supply a proper quantity of heat to the room in accordance with the setting of the draft control.

The primary air supplied beneath the fuel bed and the combustion chamber I3 is thus under automatic control. The secondary air supplied through the space 24 is always delivered in at least a minimum amount as controlled by the supply opening. This Opening is always completely open. The draft door 43 regulates the quantity of secondary air supplied above the fuel bed in amounts in addition to the minimum quantity supplied by the draft opening 40. The draft door 43 is set manually to adjust the quantity of secondary air supplied therethrough. This opening is varied in accordance with the quantityoi unconsumed products of combustion that reach the chamber 3| and fiue 29. If the unconsumed products oi combustion are quite large the draft door 43 will be opened to increase the supply of secondary air. This condition exists particularly after the combustion chamber I3 is charged with a fresh supply of fuel. After the gases evolved by the fuel upon initiation of combustion have reduced the draft door 43 can be closed to reduce the quantity of secondary air supplied above the combustion chamber I 3.

While the form of the invention 'disclosed herein i a preferred form yet it is to be understood that the features of the invention are adaptable to structural modification and'that all such modified structures as fall within the scope of the appended claim are intended to be included herein.

Having thus fully described my invention, what I claim as new. and desire to secure by Letters Patent, is:

In a stove, a vertical closed wall forming a combustion chamber, a base supporting and conforming to the contour of said wall at the back and sides butprojecting exteriorly of said wall at the front, a top having a contour conforming to said wall at the sides but projecting exteriorly of said wall at the front and back, a second wall fitting between and conforming to the projecting portions of said base and top at the front and contacting said chamber at the sides to form a fiue from base to top, there being openings in said secondary wall at said base and top whereby ambient air may circulate through said fine and be heated by said closed wall, and a third wall fitting the projecting portion of said top'at the rear and having its sides engaging said closed wall and extending downwardly to a point adjacent the base to form a second flue open at the bottom, there being an opening in said third wall adjacent said top whereby ambient air may circulate through and be heated by the chamber wall, there being an air inlet in said chamber wall adjacent the base of said second flue, means for varying the effective size of said inlet, and control means for said varying means extending upwardly through said second flue.

WILLIAM A. GRISWOLD. 

